Elastic fluid turbine power plant



July 21, 1936. A, RQSCH ELASTIC FLUID TURBINE POWER PLANT Filed Deo. 6

H|5 Attorneg.

Patented July 2l, 1936 UNITED STATES ELASTIC FLUID TURBINE POWER PLANTArthur Roach, Berlin, Germany,

eral Electric Company, York Application December 6,

assignor to Gena corporation ot New 1935, Serial No. 53,251

In Germany December 8, 1934 3 Claims.

The present invention relates to elastic fluid turbine power plants inwhich a group of turbines is provided for driving electric generatorsand at the same time for furnishing elastic fluid at a ilxed pressurefor processing or like purposes. Such elastic fluid is extracted fromthe turbine by the provision of an extraction conduit or conduitsconnected to an intermediate stage or stages of the turbine. Theinvention relates more speclflcally to the kind of power plants in whichthe high pressure end of an extraction turbine or group of turbinesincludes a Curtis type bucket wheel. Such Curtis type wheels are oftennot desirable in that they cause a considerable drop in pressure.

The object of my invention is to provide an improved arrangement of suchpower plants whereby they may be operated more economically. This isaccomplished by the provision of an auxiliary turbine connected inseries with the lower stages of the extraction turbine and the provisionof a control mechanism whereby the auxiliary turbine is normallyoperated and the Curtis type wheel run idle, effecting disconnecting ofthe auxiliary. turbine and operation of the Curtis type wheel uponfailure of the auxiliary turbine. In this manner an elastic fluidturbine installation is obtained which during normal operation operatesat best efficiency and in which maintenance of operation is insured uponfailure of the auxiliary turbine.

For a consideration of what I believe to be novel and my invention,attention is directed to the following description and the claimsappended thereto in connection with the accompanying drawing.

The single figure of the drawing represents an elastic fluid turbinepower plant embodying my invention.

The arrangement includes an extraction turbine or group of turbinescomprising a high pressure part I I1 of the Curtis type, a mediumpressure part II and a low pressure part I2 secured to a shaft I3driving an electric generator I4. Elastic fluid is suppplied from asource. in the present instance indicated as a battery of boilers I5,with superheaters I6 connected to the turbines I0, I I, I2 by conduitsI1, I8 including valve means I9, 20. The turbine I 0 has an inlet valve2I and discharges into the turbine part I I through a conduit 22including a valve 23 and a conduit 24. The conduit 24 at the same timeforms an extraction conduit and has a hand-operated valve 25. The flowot elastic fluid from the conduit 24`into the turbine part II iscontrolled by means including a valve 26. The intermediate turbine partdischarges partly into the low pressure part I2 and partly into anotherextraction conduit 21. The ilow of fluid from the intermediate turbinepart II into the low pressure turbine part I2 is 5 controlled by a valve28. The control of the valves 26 and 28 is effected automatically. Tothis end, pressure-responsive devices 29 and 30 are provided connectedby means of pipes 3i and 32 to the extraction conduits 25 and 21respectively. The 10 pressure-responsive devices 29 and 30 act upon alever 33 to which latter the valves 26 and 28 are connected. With thisarrangement the pressure or like condition of the elastic iluid in theextraction conduits 24 and 21 may be maintained 15 substantiallyconstant during changes in demand for extraction fluid. The speed of theturbine is controlled by a speed governor 34 driven from the turbineshaft and acting upon a fulcrumed lever 35, which latter is connectedthrough a lever 36 20 and a link 31 to the valve lever 33.

The arrangement so far described is known in the art and represents insubstance an extraction turbine or group of turbines with a, governingmechanism whereby the turbine valves are con- 25 trolled in response tospeed changes due to changes in demand for mechanical load output and inresponse to pressure changes in the extraction conduits due to changesin demand for extraction fluid. The mechanism also applies to 30mixed-pressure turbines to which elastic fluid is conducted tointermediate stages thereof.

The arrangement according to my invention includes an auxiliary turbine40 having an inlet valve 4I and receiving steam from the conduit 35 I6through a conduit 42. In accordance with my invention the auxiliaryturbine 40 is connected by an exhaust conduit 43 to the conduit 24whereby the exhaust of the auxiliary turbine 4U is conducted to theintermediate pressure turbine II. 40 'Ihe inlet valve 4I for theauxiliary turbine 40 is controlled in response to movements of thegoverning mechanism for the turbines II and I2, that is, in response tochanges in demand for mechanical load output and in demand for ex- 45traction steam. To this end the valve 4I is connected by a remotecontrol mechanism comprislng two pressure-responsive devices C4 and 45connected by a pipe 46, the pressure-responsive device 44 beingconnected through a lever 41 to 50 the valve 4I. The left-hand end ofthe lever 41 is connected to a speed governor 48 driven from the shaftof the turbine 40 and acting primarily as an emergency governor. 'I'hepressure-responsive device 45 is connected to a link 49 which has 55 anintermediate point connected to the lever 36 and a lower end pivotallyconnected to a lever 60. The right-hand end of the lever 60 is pivotallyconnected to a link 5I between the pressure-responsive device 3U and thelever 33. Anintermediate point of the lever 5I) is pivotally connectedto the right-hand end of a lever 62, which latter has an intermediatepoint pivoted to the valve 2| and a left-hand end secured to a relay 63.The latter is energized from a generator 64 driven by the turbine 40 insuch manner that the valve 2| is normally maintained closed.

During normal operation of the power plant, steam is conducted from theboilers I5 to the auxiliary turbine 40, whence it is discharged throughthe conduits 43 and 24 into the turbine parts II, I2. The high pressureturbine part I6 of the Curtis wheel under such condition runs idle, thevalve 23 in the conduit 22 being closed. The high pressure part I0 undersuch condition is maintained under condenser pressure by the provisionof a conduit connection 66 including a Valve 56 between the exhaust ofthe high pressure turbine part I6 and a condenser 66a connected to theexhaust of the low pressure turbine part I2. The valve 56 is open duringnormal operation of the auxiliary turbine 40.

The pressure in the extraction conduits is maintained constant byoperation of the pressure-responsive devices 29, 30. Thus, if, forinstance, the pressure in the conduit 24 drops, due to an increaseddemand for extraction fluid, the pressure-responsive device 26 causesdownward movement of the righthand end of the lever 36, effectingsimultaneous closing movement of both valves 26 and 28. Closing movementof the valve 26 causes an increase in pressure in the conduit 24 andclosing movement of the valve 23 prevents pressure drop in theextraction conduit 21 due to the decreased flow through the turbine partII. Also, during downward movement of the right-hand end of the lever 36the latter turns about its connection with the lever 36 so that theleft-hand end of the lever 36 is moved upward, effecting compression ofa fluid such as gas contained in the bellows 46, to the effect that thepressure-responsive device 44 is moved upward and effects openingmovement of the valve 4| ofthe auxiliary turbine 40, thereby increasingthe flow of elastic fluid through the auxiliary turbine and consequentlythe pressure in the conduit 24. Hence, a drop in pressure in the conduit24 causes both closing movement of the valve 26 and opening movement ofthe valve 4I. Broadly, a change in extraction-pressure or like conditionof the extraction fluid in the extraction conduit causes movement of thevalves 26 and 28 in one direction and o pposite movement of the valve4I. In contrast thereto, operation of the control mechanism by theaction of the speed governor 34 causes movement of all valves in thesame direction. For instance, an increase in speed, due to a decrease indemand for mechanical load output, causes downward movement of theleft-hand end of the lever 36 so that the right-hand end of the latteris moved downward, and through the lever 36 and the link 31 effectsclosing movement of the valves 26, 28. Under this condition the lever 36fulcrums about its right-hand end. Hence, the left-hand end of the level36 is moved downward, thereby decreasing the pressure in the bellows 45.This in turn effects a decrease in pressure in the bellows 44, resultingin closing movement of the valve 4I. If now for any reason the generator64 should fail, for instance due to a short circuit, the load isautomatically transferred from the auxiliary turbine 40 to the highpressure turbine part I0. At the same time the conduit connectionbetween the exhaust of the high pressure part I0 and the intermediatepressure turbine part II is opened and the conduit connection betweenthe exhaust of the high pressure turbine part I0 and the condenser 65ais closed. Opening of the valve 2| of the high-pressure turbine part IIIupon failure of the auxiliary generator is effected automatically bymeans of the aforementioned relay 63 which is energized from thegenerator 64. Opening of the valve 23 and closing of the valve 66 uponfailure of the auxiliary turbine 40 or its generator 64 are alsopreferably effected automatically. To this end the valves 23 and 66 areconnected to relays 61 and 68, which latter are also energized from thegenerator 64. Upon failure of the auxiliary turbine, elastic fluid isconducted to the high pressure turbine part III through the conduits |1and Il. The conduit I3 is connected by a conduit 63 including valvemeans 60 to the extraction conduit 26. The valve 60 is normally closedbut is opened in case of excessive demands for extraction steam or incase the mechanical load demand from the turbines |I, I2 is low andinsufflcient to satisfy the demand for extraction steam. The conduit 69is furthermore connected to an auxiliary boiler 6I provided primarilyfor furnishing processing steam to the extraction conduit 26 in case thedemand for processing steam exceeds the capacity of the boilers Il.

Having described the method of operation of my invention, together withthe apparatus which I now consider to represent the best embodimentthereof, I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,-

1. Elastic fluid turbine power plant including the combination ofturbine means comprising a high pressure part and low pressure partsconnected in series, a generator driven by the turbine means, anauxiliary turbine, an auxiliary generator driven by the auxiliaryturbine, control mechanisms for the turbine means and the auxiliaryturbine arranged to control the auxiliary turbine in response to changesin operating conditions of the turbine means, a conduit for connectingthe exhaust of the auxiliary turbine to the lower pressure parts of theturbine means, the high pressure part running normally idle, and meansfor automatically transferring the load from the auxiliary turbine tosaid high pressure part upon failure of the auxiliary turbine.

2. Elastic fluid turbine power plant including the combination ofturbine means comprising a high pressure part and low pressure partsconnected in series, a generator driven by the turbine means, anauxiliary turbine, an auxiliary generator driven by the auxiliaryturbine, control mechanisms for the turbine means and the auxiliaryturbine arranged to control the auxiliary turbine in response to changesin operating conditions of the turbine means, a conduit for connectingthe exhaust of the auxiliary turbine to the inlet of the low pressureparts 0f the turbine means, the high pressure part running normallyidle, means for automatically transferring the load from the auxiliaryturbine to said high pressure part upon failure of the auxiliaryturbine, extraction conduits connected to the inlet and an intermediatestage of the low pressure parts, and means including said governingmechanisms for maintaining the pressure in the extraction conduitsconstant during changes in demand for extraction uid.

3. Elastic uid turbine power plant including the combination of a highpressure turbine having a Curtis wheel, a low pressure turbine connectedin series to the high pressure turbine as regards the direction ofelastic uid therethrough, said turbines being provided on a singleshaft, a generator driven by said shaft, an extraction conduitintermediate the high pressure turbine and the low pressure turbine,speed and pressure-responsive governing mechanisms for controlling saidturbines in response to changes in demand for mechanical 1oad`output andin response to changes in demand for extraction fluid, an auxiliaryturbine having an exhaust connected to the extraction conduit wherebythe exhaust of the auxiliary turbine is normally conducted at leastpartly to the low pressure turbines, an inlet valve for the highpressure turbine, means normally maintaining the inlet valve shut, acondenser for the low pressure turbine, a conduit including a. valveconnecting thecondenser to the high the latter is pressure turbinewhereby connecting the auxiliary turbine upon failure

